The present invention relates to a rotational electric machine with an effective magnetic flux density variable in accordance with the rotational speed and a vehicle loaded therewith.
Induced electromotive force of a rotational electric machine, especially of a permanent-magnet type rotational electric machine mounted on a vehicle such as a hybrid car or an electric car, is determined on the basis of a constant magnetic flux density generated by permanent magnets disposed in a rotor and a rotational angular velocity of the rotational electric machine. That is, when the rotational angular velocity of the rotational electric machine increases, the induced electromotive force of the rotational electric machine increases in proportion to the rotational angular velocity. Hence, the permanent-magnet type rotational electric machine was able to obtain high torque power but was hardly operated in a high rotation region because the variable rotational velocity range of the machine was narrow. In the past, therefore, the high rotation region was widened by field weakening control.
Further, the conventional rotational electric machine was designed in accordance with the rotation region. Hence, when both low rotation region and high rotation region were required, rotational electric machines prepared to satisfy the regions respectively were used as described in JP-A-9-132042. Alternatively, both the drive mode and electric power generation mode were provided in one rotational electric machine so that one mode could be selected from the two modes as described in JP-A-7-298696.
The field weakening control in the background art was performed by a field weakening control current flowing in the windings of a stator. It was however necessary to raise the field weakening control current in accordance with the induced electromotive force which rose in proportion to the rotational angular velocity. Hence, heat generated in the stator windings increased. Hence, there was the possibility that lowering of efficiency in the rotational electric machine, demagnetization of permanent magnets owing to heating beyond cooling performance might occur in a high rotation region. If a plurality of rotational electric machines were prepared to satisfy the respective rotation regions, an electric power converter and a control unit were required for driving each of the rotational electric machines. This caused complication of system configuration and cost rise.
A typical object of the present invention is to provide a rotational electric machine in which high torque characteristic can be obtained in a low rotation region whereas high output power generation characteristic can be obtained in a high rotation region, and a vehicle loaded with the rotational electric machine.
Another typical object of the present invention is to provide a rotational electric machine in which high torque characteristic can be obtained in a low rotation region whereas high power generation characteristic can be obtained in a high rotation region and in which mechanical reliability can be improved, and a vehicle loaded with the rotational electric machine.
The present invention is basically characterized in that high torque characteristic and high power generation characteristic are obtained in a low rotation region and in a high rotation region respectively by mechanical control, that is, by controlling effective magnetic flux through dividing a rotor into two rotor portions. Specifically, a rotor having different-polarity field magnets arranged alternately in a rotational direction is divided into two axially separate portions. The axial position of one of the two rotor portions is changed relative to that of the other in accordance with a direction of torque of the rotor or the phase of synthesized magnetic poles of the field magnets is changed relative to that of magnetic poles of the other rotor portion in accordance with a direction of torque of the rotor. As a result, in the present invention, field weakening control can be performed even in the case where the stator windings are not supplied with any current. Moreover, according to the present invention, one of the two separate rotor portions is supported from axially opposite sides by a support mechanism to thereby relax the axially moving force of the one rotor portion.
Typical aspects of the present invention are as follows.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing an axial position of the one rotor portion relative to an axial position of the other rotor portion in accordance with a direction of torque of the rotor; the one rotor portion being supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing a phase of synthesized magnetic poles of the field magnets relative to that of magnetic poles of the other rotor portion in accordance with a direction of torque of the rotor; the one rotor portion is supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing an axial position of the one rotor portion relative to that of the other rotor portion while shifting a magnetic pole center of the field magnets disposed in the one rotor portion and another magnetic pole center of the field magnets disposed in the other rotor portion in accordance with a direction of torque of the rotor, the one rotor portion being supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing a phase of synthesized magnetic poles of the field magnets relative to that of magnetic poles of the field magnets of the other rotor portion while shifting a magnetic pole center of the field magnets disposed in the one rotor portion and another magnetic pole center of the field magnets disposed in the other rotor portion in accordance with a direction of torque of the rotor, the one rotor portion being supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing an axial position of the one rotor portion relative to that of the other rotor portion while truing up a magnetic pole center of the field magnets disposed in the one rotor portion and another magnetic pole center of the field magnets disposed in the other rotor portion in accordance with a direction of torque of the rotor, the one rotor portion being supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; and a split rotor rotatably disposed on an inner circumferential side of the stator through an air gap and axially divided into two rotor portions, the rotor portions having different-polarity field magnets disposed alternately in a rotational direction; one of the rotor portions including a changing mechanism for changing a phase of synthesized magnetic poles of the field magnets relative to that of magnetic poles of the field magnets of the other rotor portion while truing up a magnetic pole center of the field magnets disposed in the one rotor portion and another magnetic pole center of the field magnets disposed in the other rotor portion in accordance with a direction of torque of the rotor, the one rotor portion being supported from axially opposite sides by a support mechanism.
A rotational electric machine comprising: a stator having windings; a rotor having field magnets, the field magnets being constituted by a first field magnet having different-polarity magnetic poles arranged successively in a rotational direction and a second field magnet being rotatable relative to the first field magnet and having different-polarity magnetic poles arranged successively in the rotational direction; the first and second field magnets being provided opposite to magnetic poles of the stator and having a mechanism for changing a phase of synthesized magnetic poles of the first and second field magnets relative to that of magnetic poles of the first field magnet in accordance with a direction of torque of the rotor; the mechanism for changing the phase in accordance with the direction of torque having means for truing up a magnetic pole center of the first field magnet and another magnetic pole center of the second field magnet on a basis of balance between the direction of torque generated in the rotor and magnetic action force between the first and second field magnets, and means for shifting the magnetic pole centers of the first and second field magnets whenever the direction of torque generated in the rotor is inverted; the second field magnet being supported from axially opposite sides by a support mechanism.
A vehicle comprising: an internal combustion engine for driving wheels; a battery for charging and discharging electric power; a rotational electric machine mechanically linked with a crank shaft of the internal combustion engine and driven by electric power supplied from the battery to thereby drive the internal combustion engine and driven by motive power from the internal combustion engine to thereby generate electric power to be supplied to the battery; an electric power converter for controlling the rotational electric machine; a control unit for controlling the electric power converter; the rotational electric machine being constituted by any one of the above-mentioned rotational electric machines.
A vehicle comprising: a battery for charging and discharging electric power; a rotational electric machine supplied with electric power from the battery to thereby drive wheels; an electric power converter for controlling the rotational electric machine; a control unit for controlling the electric power converter; the rotational electric machine being constituted by any one of the above-mentioned rotational electric machines.
A vehicle comprising: an internal combustion engine for driving front or rear wheels; a battery for charging and discharging electric power; a rotational electric machine driven by electric power supplied from the battery to thereby drive the front or rear wheels; an electric power converter for controlling the rotational electric machine; a control unit for controlling the electric power converter; the rotational electric machine being constituted by any one of the above-mentioned rotational electric machines.
A vehicle comprising: an internal combustion engine for driving wheels; a battery for charging and discharging electric power; a rotational electric machine mechanically linked with a crank shaft of the internal combustion engine and driven by electric power supplied from the battery to thereby drive the internal combustion engine; an electric power converter for controlling the rotational electric machine; a control unit for controlling the electric power converter; the rotational electric machine being constituted by any one of the above-mentioned rotational electric machines.
A vehicle comprising: an internal combustion engine for driving wheels; a battery for charging and discharging electric power; a rotational electric machine mechanically linked with a crank shaft of the internal combustion engine and driven by motive power from the internal combustion engine to thereby generate electric power to be supplied to the battery; an electric power converter for controlling the rotational electric machine; a control unit for controlling the electric power converter; the rotational electric machine being constituted by any one of the above-mentioned rotational electric machines.